Electrochemical properties of $LiFePO_4$ cathode materials by hydrothermal route

Phospho-olivine $LiFePO_4$ cathode materials were prepared by hydrothermal reaction at different temperatures. The structural performance of $LiFePO_4$ powders were characterized by X-ray diffraction (XRD). $LiFePO_4$/Li batteries were characterized electrochemically by charge/discharge experiments. The XRD results demonstrate that $LiFePO_4$ powder has an orthorhombic olivine-type structure with a space group of Pnmb. Among the synthesized cathode materials, $LiFePO_4$synthesized at $170^{\circ}C$ and subsequently annealed at $500^{\circ}C$ shows the best electrochemical properties. It shows initial discharge capacity of $167\;mAh\;g^{-1}$ (98% of the theoretical capacity) close to the theoretical capacity of $LiFePO_4$ ($170\;mAh\;g^{-1}$) at 0.1 C rate, which is ascribed to the enhanced degree of crystallinity, better phase purity, more spherical and more finely dispersed nanoparticles, crystallization and activation of small amount impurity.